The effect of hormone therapy on lactation-induced bone loss study is proposed to compare the "potential beneficial effects" of low dose contraceptive pills in the prevention of lactation induced demineralization. A randomized study is proposed to compare Loestrin (an estrogen-containing agent) with Micronov (a progesterone agent). Contraceptives will be administered in the normal dose from 4 weeks to 6 months post-delivery. Bone mineralization will be assessed by DEXA at the onset of contraception therapy and at 6 months post-delivery.